Dissatisfied Groupon Customer

I bought a coupon on groupon for a microdermabrasion. Found a place where i wanted to do this. Could not get in touch with Body and Beauty Retreat. Tried about three times. Called Groupon to cancel this voucher. The client refused to cancel this voucher as she had redeemed the voucher and Groupon said I must go back to the client and redeem this voucher. How can i go back when i already had words with this company. How can i feel comfortable knowing i had reported her to Groupon. I asked Groupon to please refund me and they refused at least i could use the voucher on another retreat. I am so dissapointed as i feel some of these companies are redeeming the vouchers and not getting back to customers. Shoudnt the voucher only be redeemed once the customer has used it. Please not happy with customer service at Groupon at all.